The subject matter disclosed herein relates to detection systems for use in imaging systems, such as nuclear medicine imaging systems.
Diagnostic imaging technologies allow images of the internal structures of a patient to be obtained and may provide information about the function and integrity of the patient's internal structures. Diagnostic imaging systems may operate based on various physical principles, including the radiation emission from or transmission through the patient tissues. For example, single photon emission computed tomography (SPECT) and positron emission tomography (PET) may utilize a radiopharmaceutical that is administered to a patient and whose decay results in the emission of gamma rays from locations within the patient's body. The radiopharmaceutical is typically selected so as to be preferentially or differentially distributed in the body based on the physiological or biochemical processes in the body. For example, a radiopharmaceutical may be selected that is preferentially processed or taken up by tumor tissue. In such an example, the radiopharmaceutical will typically be disposed in greater concentrations around tumor tissue within the patient.
In the context of PET imaging, the radiopharmaceutical produces a positron particle during its decay process. The positron combines with an electron in the patient to produce two annihilation photons (511 KeV gammas) which travel in opposite directions. In SPECT imaging, a single gamma ray is generated when the radiopharmaceutical breaks down or decays within the patient. These gamma rays interact with detection mechanisms within the respective PET or SPECT scanner, which allow the decay events to be localized, thereby providing a view of where the radiopharmaceutical is distributed throughout the patient. In this manner, a caregiver can visualize where in the patient the radiopharmaceutical is disproportionately distributed and may thereby identify where physiological structures and/or biochemical processes of diagnostic significance are located within the patient.
One issue that may arise is that, in certain detector technologies, noise or dark counts may also be generated, such as due to the electronic noise or background effects. Such dark counts may be indistinguishable from the desired signal and may reduce the linear dynamic range of the readout electronics.